Commit message: Fix a bug when getting a gzip header extra field with inflate().

If the extra field was larger than the space the user provided with
inflateGetHeader(), and if multiple calls of inflate() delivered
the extra header data, then there could be a buffer overflow of the
provided space. This commit assures that provided space is not
exceeded.
CVE: CVE-2022-37434
CWE: CWE-787
Vulnerability description: zlib through 1.2.12 has a heap-based buffer over-read or buffer overflow in inflate in inflate.c via a large gzip header extra field. NOTE: only applications that call inflateGetHeader are affected. Some common applications bundle the affected zlib source code but may be unable to call inflateGetHeader (e.g., see the nodejs/node reference).

Project: zlib
File: inflate.c

unsigned long ZEXPORT inflateCodesUsed(strm)
z_streamp strm;
{
    struct inflate_state FAR *state;
    if (inflateStateCheck(strm)) return (unsigned long)-1;
    state = (struct inflate_state FAR *)strm->state;
    return (unsigned long)(state->next - state->codes);
}

Project: zlib
File: inflate.c

int ZEXPORT inflate(strm, flush)
z_streamp strm;
int flush;
{
    struct inflate_state FAR *state;
    z_const unsigned char FAR *next;    /* next input */
    unsigned char FAR *put;     /* next output */
    unsigned have, left;        /* available input and output */
    unsigned long hold;         /* bit buffer */
    unsigned bits;              /* bits in bit buffer */
    unsigned in, out;           /* save starting available input and output */
    unsigned copy;              /* number of stored or match bytes to copy */
    unsigned char FAR *from;    /* where to copy match bytes from */
    code here;                  /* current decoding table entry */
    code last;                  /* parent table entry */
    unsigned len;               /* length to copy for repeats, bits to drop */
    int ret;                    /* return code */
#ifdef GUNZIP
    unsigned char hbuf[4];      /* buffer for gzip header crc calculation */
#endif
    static const unsigned short order[19] = /* permutation of code lengths */
        {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};

    if (inflateStateCheck(strm) || strm->next_out == Z_NULL ||
        (strm->next_in == Z_NULL && strm->avail_in != 0))
        return Z_STREAM_ERROR;

    state = (struct inflate_state FAR *)strm->state;
    if (state->mode == TYPE) state->mode = TYPEDO;      /* skip check */
    LOAD();
    in = have;
    out = left;
    ret = Z_OK;
    for (;;)
        switch (state->mode) {
        case HEAD:
            if (state->wrap == 0) {
                state->mode = TYPEDO;
                break;
            }
            NEEDBITS(16);
#ifdef GUNZIP
            if ((state->wrap & 2) && hold == 0x8b1f) {  /* gzip header */
                if (state->wbits == 0)
                    state->wbits = 15;
                state->check = crc32(0L, Z_NULL, 0);
                CRC2(state->check, hold);
                INITBITS();
                state->mode = FLAGS;
                break;
            }
            if (state->head != Z_NULL)
                state->head->done = -1;
            if (!(state->wrap & 1) ||   /* check if zlib header allowed */
#else
            if (
#endif
                ((BITS(8) << 8) + (hold >> 8)) % 31) {
                strm->msg = (char *)"incorrect header check";
                state->mode = BAD;
                break;
            }
            if (BITS(4) != Z_DEFLATED) {
                strm->msg = (char *)"unknown compression method";
                state->mode = BAD;
                break;
            }
            DROPBITS(4);
            len = BITS(4) + 8;
            if (state->wbits == 0)
                state->wbits = len;
            if (len > 15 || len > state->wbits) {
                strm->msg = (char *)"invalid window size";
                state->mode = BAD;
                break;
            }
            state->dmax = 1U << len;
            state->flags = 0;               /* indicate zlib header */
            Tracev((stderr, "inflate:   zlib header ok\n"));
            strm->adler = state->check = adler32(0L, Z_NULL, 0);
            state->mode = hold & 0x200 ? DICTID : TYPE;
            INITBITS();
            break;
#ifdef GUNZIP
        case FLAGS:
            NEEDBITS(16);
            state->flags = (int)(hold);
            if ((state->flags & 0xff) != Z_DEFLATED) {
                strm->msg = (char *)"unknown compression method";
                state->mode = BAD;
                break;
            }
            if (state->flags & 0xe000) {
                strm->msg = (char *)"unknown header flags set";
                state->mode = BAD;
                break;
            }
            if (state->head != Z_NULL)
                state->head->text = (int)((hold >> 8) & 1);
            if ((state->flags & 0x0200) && (state->wrap & 4))
                CRC2(state->check, hold);
            INITBITS();
            state->mode = TIME;
                /* fallthrough */
        case TIME:
            NEEDBITS(32);
            if (state->head != Z_NULL)
                state->head->time = hold;
            if ((state->flags & 0x0200) && (state->wrap & 4))
                CRC4(state->check, hold);
            INITBITS();
            state->mode = OS;
                /* fallthrough */
        case OS:
            NEEDBITS(16);
            if (state->head != Z_NULL) {
                state->head->xflags = (int)(hold & 0xff);
                state->head->os = (int)(hold >> 8);
            }
            if ((state->flags & 0x0200) && (state->wrap & 4))
                CRC2(state->check, hold);
            INITBITS();
            state->mode = EXLEN;
                /* fallthrough */
        case EXLEN:
            if (state->flags & 0x0400) {
                NEEDBITS(16);
                state->length = (unsigned)(hold);
                if (state->head != Z_NULL)
                    state->head->extra_len = (unsigned)hold;
                if ((state->flags & 0x0200) && (state->wrap & 4))
                    CRC2(state->check, hold);
                INITBITS();
            }
            else if (state->head != Z_NULL)
                state->head->extra = Z_NULL;
            state->mode = EXTRA;
                /* fallthrough */
        case EXTRA:
            if (state->flags & 0x0400) {
                copy = state->length;
                if (copy > have) copy = have;
                if (copy) {
                    len = state->head->extra_len - state->length;
                    if (state->head != Z_NULL &&
                        state->head->extra != Z_NULL &&
                        len < state->head->extra_max) {
                        zmemcpy(state->head->extra + len, next,
                                len + copy > state->head->extra_max ?
                                state->head->extra_max - len : copy);
                    }
                    if ((state->flags & 0x0200) && (state->wrap & 4))
                        state->check = crc32(state->check, next, copy);
                    have -= copy;
                    next += copy;
                    state->length -= copy;
                }
                if (state->length) goto inf_leave;
            }
            state->length = 0;
            state->mode = NAME;
                /* fallthrough */
        case NAME:
            if (state->flags & 0x0800) {
                if (have == 0) goto inf_leave;
                copy = 0;
                do {
                    len = (unsigned)(next[copy++]);
                    if (state->head != Z_NULL &&
                            state->head->name != Z_NULL &&
                            state->length < state->head->name_max)
                        state->head->name[state->length++] = (Bytef)len;
                } while (len && copy < have);
                if ((state->flags & 0x0200) && (state->wrap & 4))
                    state->check = crc32(state->check, next, copy);
                have -= copy;
                next += copy;
                if (len) goto inf_leave;
            }
            else if (state->head != Z_NULL)
                state->head->name = Z_NULL;
            state->length = 0;
            state->mode = COMMENT;
                /* fallthrough */
        case COMMENT:
            if (state->flags & 0x1000) {
                if (have == 0) goto inf_leave;
                copy = 0;
                do {
                    len = (unsigned)(next[copy++]);
                    if (state->head != Z_NULL &&
                            state->head->comment != Z_NULL &&
                            state->length < state->head->comm_max)
                        state->head->comment[state->length++] = (Bytef)len;
                } while (len && copy < have);
                if ((state->flags & 0x0200) && (state->wrap & 4))
                    state->check = crc32(state->check, next, copy);
                have -= copy;
                next += copy;
                if (len) goto inf_leave;
            }
            else if (state->head != Z_NULL)
                state->head->comment = Z_NULL;
            state->mode = HCRC;
                /* fallthrough */
        case HCRC:
            if (state->flags & 0x0200) {
                NEEDBITS(16);
                if ((state->wrap & 4) && hold != (state->check & 0xffff)) {
                    strm->msg = (char *)"header crc mismatch";
                    state->mode = BAD;
                    break;
                }
                INITBITS();
            }
            if (state->head != Z_NULL) {
                state->head->hcrc = (int)((state->flags >> 9) & 1);
                state->head->done = 1;
            }
            strm->adler = state->check = crc32(0L, Z_NULL, 0);
            state->mode = TYPE;
            break;
#endif
        case DICTID:
            NEEDBITS(32);
            strm->adler = state->check = ZSWAP32(hold);
            INITBITS();
            state->mode = DICT;
                /* fallthrough */
        case DICT:
            if (state->havedict == 0) {
                RESTORE();
                return Z_NEED_DICT;
            }
            strm->adler = state->check = adler32(0L, Z_NULL, 0);
            state->mode = TYPE;
                /* fallthrough */
        case TYPE:
            if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave;
                /* fallthrough */
        case TYPEDO:
            if (state->last) {
                BYTEBITS();
                state->mode = CHECK;
                break;
            }
            NEEDBITS(3);
            state->last = BITS(1);
            DROPBITS(1);
            switch (BITS(2)) {
            case 0:                             /* stored block */
                Tracev((stderr, "inflate:     stored block%s\n",
                        state->last ? " (last)" : ""));
                state->mode = STORED;
                break;
            case 1:                             /* fixed block */
                fixedtables(state);
                Tracev((stderr, "inflate:     fixed codes block%s\n",
                        state->last ? " (last)" : ""));
                state->mode = LEN_;             /* decode codes */
                if (flush == Z_TREES) {
                    DROPBITS(2);
                    goto inf_leave;
                }
                break;
            case 2:                             /* dynamic block */
                Tracev((stderr, "inflate:     dynamic codes block%s\n",
                        state->last ? " (last)" : ""));
                state->mode = TABLE;
                break;
            case 3:
                strm->msg = (char *)"invalid block type";
                state->mode = BAD;
            }
            DROPBITS(2);
            break;
        case STORED:
            BYTEBITS();                         /* go to byte boundary */
            NEEDBITS(32);
            if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
                strm->msg = (char *)"invalid stored block lengths";
                state->mode = BAD;
                break;
            }
            state->length = (unsigned)hold & 0xffff;
            Tracev((stderr, "inflate:       stored length %u\n",
                    state->length));
            INITBITS();
            state->mode = COPY_;
            if (flush == Z_TREES) goto inf_leave;
                /* fallthrough */
        case COPY_:
            state->mode = COPY;
                /* fallthrough */
        case COPY:
            copy = state->length;
            if (copy) {
                if (copy > have) copy = have;
                if (copy > left) copy = left;
                if (copy == 0) goto inf_leave;
                zmemcpy(put, next, copy);
                have -= copy;
                next += copy;
                left -= copy;
                put += copy;
                state->length -= copy;
                break;
            }
            Tracev((stderr, "inflate:       stored end\n"));
            state->mode = TYPE;
            break;
        case TABLE:
            NEEDBITS(14);
            state->nlen = BITS(5) + 257;
            DROPBITS(5);
            state->ndist = BITS(5) + 1;
            DROPBITS(5);
            state->ncode = BITS(4) + 4;
            DROPBITS(4);
#ifndef PKZIP_BUG_WORKAROUND
            if (state->nlen > 286 || state->ndist > 30) {
                strm->msg = (char *)"too many length or distance symbols";
                state->mode = BAD;
                break;
            }
#endif
            Tracev((stderr, "inflate:       table sizes ok\n"));
            state->have = 0;
            state->mode = LENLENS;
                /* fallthrough */
        case LENLENS:
            while (state->have < state->ncode) {
                NEEDBITS(3);
                state->lens[order[state->have++]] = (unsigned short)BITS(3);
                DROPBITS(3);
            }
            while (state->have < 19)
                state->lens[order[state->have++]] = 0;
            state->next = state->codes;
            state->lencode = (const code FAR *)(state->next);
            state->lenbits = 7;
            ret = inflate_table(CODES, state->lens, 19, &(state->next),
                                &(state->lenbits), state->work);
            if (ret) {
                strm->msg = (char *)"invalid code lengths set";
                state->mode = BAD;
                break;
            }
            Tracev((stderr, "inflate:       code lengths ok\n"));
            state->have = 0;
            state->mode = CODELENS;
                /* fallthrough */
        case CODELENS:
            while (state->have < state->nlen + state->ndist) {
                for (;;) {
                    here = state->lencode[BITS(state->lenbits)];
                    if ((unsigned)(here.bits) <= bits) break;
                    PULLBYTE();
                }
                if (here.val < 16) {
                    DROPBITS(here.bits);
                    state->lens[state->have++] = here.val;
                }
                else {
                    if (here.val == 16) {
                        NEEDBITS(here.bits + 2);
                        DROPBITS(here.bits);
                        if (state->have == 0) {
                            strm->msg = (char *)"invalid bit length repeat";
                            state->mode = BAD;
                            break;
                        }
                        len = state->lens[state->have - 1];
                        copy = 3 + BITS(2);
                        DROPBITS(2);
                    }
                    else if (here.val == 17) {
                        NEEDBITS(here.bits + 3);
                        DROPBITS(here.bits);
                        len = 0;
                        copy = 3 + BITS(3);
                        DROPBITS(3);
                    }
                    else {
                        NEEDBITS(here.bits + 7);
                        DROPBITS(here.bits);
                        len = 0;
                        copy = 11 + BITS(7);
                        DROPBITS(7);
                    }
                    if (state->have + copy > state->nlen + state->ndist) {
                        strm->msg = (char *)"invalid bit length repeat";
                        state->mode = BAD;
                        break;
                    }
                    while (copy--)
                        state->lens[state->have++] = (unsigned short)len;
                }
            }

            /* handle error breaks in while */
            if (state->mode == BAD) break;

            /* check for end-of-block code (better have one) */
            if (state->lens[256] == 0) {
                strm->msg = (char *)"invalid code -- missing end-of-block";
                state->mode = BAD;
                break;
            }

            /* build code tables -- note: do not change the lenbits or distbits
               values here (9 and 6) without reading the comments in inftrees.h
               concerning the ENOUGH constants, which depend on those values */
            state->next = state->codes;
            state->lencode = (const code FAR *)(state->next);
            state->lenbits = 9;
            ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
                                &(state->lenbits), state->work);
            if (ret) {
                strm->msg = (char *)"invalid literal/lengths set";
                state->mode = BAD;
                break;
            }
            state->distcode = (const code FAR *)(state->next);
            state->distbits = 6;
            ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
                            &(state->next), &(state->distbits), state->work);
            if (ret) {
                strm->msg = (char *)"invalid distances set";
                state->mode = BAD;
                break;
            }
            Tracev((stderr, "inflate:       codes ok\n"));
            state->mode = LEN_;
            if (flush == Z_TREES) goto inf_leave;
                /* fallthrough */
        case LEN_:
            state->mode = LEN;
                /* fallthrough */
        case LEN:
            if (have >= 6 && left >= 258) {
                RESTORE();
                inflate_fast(strm, out);
                LOAD();
                if (state->mode == TYPE)
                    state->back = -1;
                break;
            }
            state->back = 0;
            for (;;) {
                here = state->lencode[BITS(state->lenbits)];
                if ((unsigned)(here.bits) <= bits) break;
                PULLBYTE();
            }
            if (here.op && (here.op & 0xf0) == 0) {
                last = here;
                for (;;) {
                    here = state->lencode[last.val +
                            (BITS(last.bits + last.op) >> last.bits)];
                    if ((unsigned)(last.bits + here.bits) <= bits) break;
                    PULLBYTE();
                }
                DROPBITS(last.bits);
                state->back += last.bits;
            }
            DROPBITS(here.bits);
            state->back += here.bits;
            state->length = (unsigned)here.val;
            if ((int)(here.op) == 0) {
                Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
                        "inflate:         literal '%c'\n" :
                        "inflate:         literal 0x%02x\n", here.val));
                state->mode = LIT;
                break;
            }
            if (here.op & 32) {
                Tracevv((stderr, "inflate:         end of block\n"));
                state->back = -1;
                state->mode = TYPE;
                break;
            }
            if (here.op & 64) {
                strm->msg = (char *)"invalid literal/length code";
                state->mode = BAD;
                break;
            }
            state->extra = (unsigned)(here.op) & 15;
            state->mode = LENEXT;
                /* fallthrough */
        case LENEXT:
            if (state->extra) {
                NEEDBITS(state->extra);
                state->length += BITS(state->extra);
                DROPBITS(state->extra);
                state->back += state->extra;
            }
            Tracevv((stderr, "inflate:         length %u\n", state->length));
            state->was = state->length;
            state->mode = DIST;
                /* fallthrough */
        case DIST:
            for (;;) {
                here = state->distcode[BITS(state->distbits)];
                if ((unsigned)(here.bits) <= bits) break;
                PULLBYTE();
            }
            if ((here.op & 0xf0) == 0) {
                last = here;
                for (;;) {
                    here = state->distcode[last.val +
                            (BITS(last.bits + last.op) >> last.bits)];
                    if ((unsigned)(last.bits + here.bits) <= bits) break;
                    PULLBYTE();
                }
                DROPBITS(last.bits);
                state->back += last.bits;
            }
            DROPBITS(here.bits);
            state->back += here.bits;
            if (here.op & 64) {
                strm->msg = (char *)"invalid distance code";
                state->mode = BAD;
                break;
            }
            state->offset = (unsigned)here.val;
            state->extra = (unsigned)(here.op) & 15;
            state->mode = DISTEXT;
                /* fallthrough */
        case DISTEXT:
            if (state->extra) {
                NEEDBITS(state->extra);
                state->offset += BITS(state->extra);
                DROPBITS(state->extra);
                state->back += state->extra;
            }
#ifdef INFLATE_STRICT
            if (state->offset > state->dmax) {
                strm->msg = (char *)"invalid distance too far back";
                state->mode = BAD;
                break;
            }
#endif
            Tracevv((stderr, "inflate:         distance %u\n", state->offset));
            state->mode = MATCH;
                /* fallthrough */
        case MATCH:
            if (left == 0) goto inf_leave;
            copy = out - left;
            if (state->offset > copy) {         /* copy from window */
                copy = state->offset - copy;
                if (copy > state->whave) {
                    if (state->sane) {
                        strm->msg = (char *)"invalid distance too far back";
                        state->mode = BAD;
                        break;
                    }
#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
                    Trace((stderr, "inflate.c too far\n"));
                    copy -= state->whave;
                    if (copy > state->length) copy = state->length;
                    if (copy > left) copy = left;
                    left -= copy;
                    state->length -= copy;
                    do {
                        *put++ = 0;
                    } while (--copy);
                    if (state->length == 0) state->mode = LEN;
                    break;
#endif
                }
                if (copy > state->wnext) {
                    copy -= state->wnext;
                    from = state->window + (state->wsize - copy);
                }
                else
                    from = state->window + (state->wnext - copy);
                if (copy > state->length) copy = state->length;
            }
            else {                              /* copy from output */
                from = put - state->offset;
                copy = state->length;
            }
            if (copy > left) copy = left;
            left -= copy;
            state->length -= copy;
            do {
                *put++ = *from++;
            } while (--copy);
            if (state->length == 0) state->mode = LEN;
            break;
        case LIT:
            if (left == 0) goto inf_leave;
            *put++ = (unsigned char)(state->length);
            left--;
            state->mode = LEN;
            break;
        case CHECK:
            if (state->wrap) {
                NEEDBITS(32);
                out -= left;
                strm->total_out += out;
                state->total += out;
                if ((state->wrap & 4) && out)
                    strm->adler = state->check =
                        UPDATE_CHECK(state->check, put - out, out);
                out = left;
                if ((state->wrap & 4) && (
#ifdef GUNZIP
                     state->flags ? hold :
#endif
                     ZSWAP32(hold)) != state->check) {
                    strm->msg = (char *)"incorrect data check";
                    state->mode = BAD;
                    break;
                }
                INITBITS();
                Tracev((stderr, "inflate:   check matches trailer\n"));
            }
#ifdef GUNZIP
            state->mode = LENGTH;
                /* fallthrough */
        case LENGTH:
            if (state->wrap && state->flags) {
                NEEDBITS(32);
                if ((state->wrap & 4) && hold != (state->total & 0xffffffff)) {
                    strm->msg = (char *)"incorrect length check";
                    state->mode = BAD;
                    break;
                }
                INITBITS();
                Tracev((stderr, "inflate:   length matches trailer\n"));
            }
#endif
            state->mode = DONE;
                /* fallthrough */
        case DONE:
            ret = Z_STREAM_END;
            goto inf_leave;
        case BAD:
            ret = Z_DATA_ERROR;
            goto inf_leave;
        case MEM:
            return Z_MEM_ERROR;
        case SYNC:
                /* fallthrough */
        default:
            return Z_STREAM_ERROR;
        }

    /*
       Return from inflate(), updating the total counts and the check value.
       If there was no progress during the inflate() call, return a buffer
       error.  Call updatewindow() to create and/or update the window state.
       Note: a memory error from inflate() is non-recoverable.
     */
  inf_leave:
    RESTORE();
    if (state->wsize || (out != strm->avail_out && state->mode < BAD &&
            (state->mode < CHECK || flush != Z_FINISH)))
        if (updatewindow(strm, strm->next_out, out - strm->avail_out)) {
            state->mode = MEM;
            return Z_MEM_ERROR;
        }
    in -= strm->avail_in;
    out -= strm->avail_out;
    strm->total_in += in;
    strm->total_out += out;
    state->total += out;
    if ((state->wrap & 4) && out)
        strm->adler = state->check =
            UPDATE_CHECK(state->check, strm->next_out - out, out);
    strm->data_type = (int)state->bits + (state->last ? 64 : 0) +
                      (state->mode == TYPE ? 128 : 0) +
                      (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0);
    if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
        ret = Z_BUF_ERROR;
    return ret;
}

Project: zlib
File: inflate.c

int ZEXPORT inflateEnd(strm)
z_streamp strm;
{
    struct inflate_state FAR *state;
    if (inflateStateCheck(strm))
        return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    if (state->window != Z_NULL) ZFREE(strm, state->window);
    ZFREE(strm, strm->state);
    strm->state = Z_NULL;
    Tracev((stderr, "inflate: end\n"));
    return Z_OK;
}

Project: zlib
File: inflate.c

int ZEXPORT inflateReset(strm)
z_streamp strm;
{
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    state->wsize = 0;
    state->whave = 0;
    state->wnext = 0;
    return inflateResetKeep(strm);
}

Project: zlib
File: inflate.c

int ZEXPORT inflateUndermine(strm, subvert)
z_streamp strm;
int subvert;
{
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
    state->sane = !subvert;
    return Z_OK;
#else
    (void)subvert;
    state->sane = 1;
    return Z_DATA_ERROR;
#endif
}

Project: zlib
File: inflate.c

local int inflateStateCheck(strm)
z_streamp strm;
{
    struct inflate_state FAR *state;
    if (strm == Z_NULL ||
        strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
        return 1;
    state = (struct inflate_state FAR *)strm->state;
    if (state == Z_NULL || state->strm != strm ||
        state->mode < HEAD || state->mode > SYNC)
        return 1;
    return 0;
}

Project: zlib
File: inflate.c

int ZEXPORT inflateReset2(strm, windowBits)
z_streamp strm;
int windowBits;
{
    int wrap;
    struct inflate_state FAR *state;

    /* get the state */
    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;

    /* extract wrap request from windowBits parameter */
    if (windowBits < 0) {
        wrap = 0;
        windowBits = -windowBits;
    }
    else {
        wrap = (windowBits >> 4) + 5;
#ifdef GUNZIP
        if (windowBits < 48)
            windowBits &= 15;
#endif
    }

    /* set number of window bits, free window if different */
    if (windowBits && (windowBits < 8 || windowBits > 15))
        return Z_STREAM_ERROR;
    if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
        ZFREE(strm, state->window);
        state->window = Z_NULL;
    }

    /* update state and reset the rest of it */
    state->wrap = wrap;
    state->wbits = (unsigned)windowBits;
    return inflateReset(strm);
}

Project: zlib
File: inflate.c

long ZEXPORT inflateMark(strm)
z_streamp strm;
{
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm))
        return -(1L << 16);
    state = (struct inflate_state FAR *)strm->state;
    return (long)(((unsigned long)((long)state->back)) << 16) +
        (state->mode == COPY ? state->length :
            (state->mode == MATCH ? state->was - state->length : 0));
}

Project: zlib
File: inflate.c

int ZEXPORT inflateCopy(dest, source)
z_streamp dest;
z_streamp source;
{
    struct inflate_state FAR *state;
    struct inflate_state FAR *copy;
    unsigned char FAR *window;
    unsigned wsize;

    /* check input */
    if (inflateStateCheck(source) || dest == Z_NULL)
        return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)source->state;

    /* allocate space */
    copy = (struct inflate_state FAR *)
           ZALLOC(source, 1, sizeof(struct inflate_state));
    if (copy == Z_NULL) return Z_MEM_ERROR;
    window = Z_NULL;
    if (state->window != Z_NULL) {
        window = (unsigned char FAR *)
                 ZALLOC(source, 1U << state->wbits, sizeof(unsigned char));
        if (window == Z_NULL) {
            ZFREE(source, copy);
            return Z_MEM_ERROR;
        }
    }

    /* copy state */
    zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
    zmemcpy((voidpf)copy, (voidpf)state, sizeof(struct inflate_state));
    copy->strm = dest;
    if (state->lencode >= state->codes &&
        state->lencode <= state->codes + ENOUGH - 1) {
        copy->lencode = copy->codes + (state->lencode - state->codes);
        copy->distcode = copy->codes + (state->distcode - state->codes);
    }
    copy->next = copy->codes + (state->next - state->codes);
    if (window != Z_NULL) {
        wsize = 1U << state->wbits;
        zmemcpy(window, state->window, wsize);
    }
    copy->window = window;
    dest->state = (struct internal_state FAR *)copy;
    return Z_OK;
}

Project: zlib
File: inflate.c

int ZEXPORT inflateValidate(strm, check)
z_streamp strm;
int check;
{
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    if (check && state->wrap)
        state->wrap |= 4;
    else
        state->wrap &= ~4;
    return Z_OK;
}

Project: zlib
File: inflate.c

int ZEXPORT inflateGetDictionary(strm, dictionary, dictLength)
z_streamp strm;
Bytef *dictionary;
uInt *dictLength;
{
    struct inflate_state FAR *state;

    /* check state */
    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;

    /* copy dictionary */
    if (state->whave && dictionary != Z_NULL) {
        zmemcpy(dictionary, state->window + state->wnext,
                state->whave - state->wnext);
        zmemcpy(dictionary + state->whave - state->wnext,
                state->window, state->wnext);
    }
    if (dictLength != Z_NULL)
        *dictLength = state->whave;
    return Z_OK;
}

Project: zlib
File: inflate.c

int ZEXPORT inflatePrime(strm, bits, value)
z_streamp strm;
int bits;
int value;
{
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    if (bits < 0) {
        state->hold = 0;
        state->bits = 0;
        return Z_OK;
    }
    if (bits > 16 || state->bits + (uInt)bits > 32) return Z_STREAM_ERROR;
    value &= (1L << bits) - 1;
    state->hold += (unsigned)value << state->bits;
    state->bits += (uInt)bits;
    return Z_OK;
}

Project: zlib
File: inflate.c

int ZEXPORT inflateSync(strm)
z_streamp strm;
{
    unsigned len;               /* number of bytes to look at or looked at */
    int flags;                  /* temporary to save header status */
    unsigned long in, out;      /* temporary to save total_in and total_out */
    unsigned char buf[4];       /* to restore bit buffer to byte string */
    struct inflate_state FAR *state;

    /* check parameters */
    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;

    /* if first time, start search in bit buffer */
    if (state->mode != SYNC) {
        state->mode = SYNC;
        state->hold <<= state->bits & 7;
        state->bits -= state->bits & 7;
        len = 0;
        while (state->bits >= 8) {
            buf[len++] = (unsigned char)(state->hold);
            state->hold >>= 8;
            state->bits -= 8;
        }
        state->have = 0;
        syncsearch(&(state->have), buf, len);
    }

    /* search available input */
    len = syncsearch(&(state->have), strm->next_in, strm->avail_in);
    strm->avail_in -= len;
    strm->next_in += len;
    strm->total_in += len;

    /* return no joy or set up to restart inflate() on a new block */
    if (state->have != 4) return Z_DATA_ERROR;
    if (state->flags == -1)
        state->wrap = 0;    /* if no header yet, treat as raw */
    else
        state->wrap &= ~4;  /* no point in computing a check value now */
    flags = state->flags;
    in = strm->total_in;  out = strm->total_out;
    inflateReset(strm);
    strm->total_in = in;  strm->total_out = out;
    state->flags = flags;
    state->mode = TYPE;
    return Z_OK;
}

Project: zlib
File: inflate.c

int ZEXPORT inflateSyncPoint(strm)
z_streamp strm;
{
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    return state->mode == STORED && state->bits == 0;
}

Project: zlib
File: inflate.c

int ZEXPORT inflateSetDictionary(strm, dictionary, dictLength)
z_streamp strm;
const Bytef *dictionary;
uInt dictLength;
{
    struct inflate_state FAR *state;
    unsigned long dictid;
    int ret;

    /* check state */
    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    if (state->wrap != 0 && state->mode != DICT)
        return Z_STREAM_ERROR;

    /* check for correct dictionary identifier */
    if (state->mode == DICT) {
        dictid = adler32(0L, Z_NULL, 0);
        dictid = adler32(dictid, dictionary, dictLength);
        if (dictid != state->check)
            return Z_DATA_ERROR;
    }

    /* copy dictionary to window using updatewindow(), which will amend the
       existing dictionary if appropriate */
    ret = updatewindow(strm, dictionary + dictLength, dictLength);
    if (ret) {
        state->mode = MEM;
        return Z_MEM_ERROR;
    }
    state->havedict = 1;
    Tracev((stderr, "inflate:   dictionary set\n"));
    return Z_OK;
}

Project: zlib
File: inflate.c

int ZEXPORT inflateGetHeader(strm, head)
z_streamp strm;
gz_headerp head;
{
    struct inflate_state FAR *state;

    /* check state */
    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    if ((state->wrap & 2) == 0) return Z_STREAM_ERROR;

    /* save header structure */
    state->head = head;
    head->done = 0;
    return Z_OK;
}

Project: zlib
File: inflate.c

int ZEXPORT inflateResetKeep(strm)
z_streamp strm;
{
    struct inflate_state FAR *state;

    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;
    strm->total_in = strm->total_out = state->total = 0;
    strm->msg = Z_NULL;
    if (state->wrap)        /* to support ill-conceived Java test suite */
        strm->adler = state->wrap & 1;
    state->mode = HEAD;
    state->last = 0;
    state->havedict = 0;
    state->flags = -1;
    state->dmax = 32768U;
    state->head = Z_NULL;
    state->hold = 0;
    state->bits = 0;
    state->lencode = state->distcode = state->next = state->codes;
    state->sane = 1;
    state->back = -1;
    Tracev((stderr, "inflate: reset\n"));
    return Z_OK;
}

Project: zlib
File: inflate.c

int ZEXPORT inflateInit2_(strm, windowBits, version, stream_size)
z_streamp strm;
int windowBits;
const char *version;
int stream_size;
{
    int ret;
    struct inflate_state FAR *state;

    if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
        stream_size != (int)(sizeof(z_stream)))
        return Z_VERSION_ERROR;
    if (strm == Z_NULL) return Z_STREAM_ERROR;
    strm->msg = Z_NULL;                 /* in case we return an error */
    if (strm->zalloc == (alloc_func)0) {
#ifdef Z_SOLO
        return Z_STREAM_ERROR;
#else
        strm->zalloc = zcalloc;
        strm->opaque = (voidpf)0;
#endif
    }
    if (strm->zfree == (free_func)0)
#ifdef Z_SOLO
        return Z_STREAM_ERROR;
#else
        strm->zfree = zcfree;
#endif
    state = (struct inflate_state FAR *)
            ZALLOC(strm, 1, sizeof(struct inflate_state));
    if (state == Z_NULL) return Z_MEM_ERROR;
    Tracev((stderr, "inflate: allocated\n"));
    strm->state = (struct internal_state FAR *)state;
    state->strm = strm;
    state->window = Z_NULL;
    state->mode = HEAD;     /* to pass state test in inflateReset2() */
    ret = inflateReset2(strm, windowBits);
    if (ret != Z_OK) {
        ZFREE(strm, state);
        strm->state = Z_NULL;
    }
    return ret;
}